I had a similar problem with my BX23S with a Curtis cab. The lights on the cab are fused off of the battery, and not the fuse block. The power wire runs up the right A-pillar to the roof of the cab and then to the switches. There are also small white push-button circuit breakers directly under each one of my switches, that you push to reset unless you have a failure of the main power line. After a lot of digging, I found the fuse to the right of the battery and it was pushed behind some other wiring. Took me about 4 hours of tracing wires, etc. I looked at it carefully, and thought about extending it outside of its original location, but decided that it would be more work than I cared to do. If I were to do the work, I would install a Carling Technologies push-button circuit breaker somewhere on the dash that would be an easy reset.